Parallel, miniaturized scanning probe microscope for defect inspection and review

Sadeghian, Hamed; Dool, T.C. van den; Crowcombe, Will; Herfst, R.W.; Winters, Jasper; Kramer, Geerten; Koster, N.B.

doi:10.1117/12.2045557

Cited by 9 publications

(7 citation statements)

References 5 publications

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“…In this paper we explore whether speed of AFM might be increased enough that it becomes a viable candidate for full blank inspection. Even the fastest AFM systems in development today 2,3 are about 4 orders of magnitude too slow for this task. We will review practical and physical limits defining measurement speed of AFM including measurements showing various of the issues discussed.…”

Section: Introductionmentioning

confidence: 99%

EUV blank defect and particle inspection with high throughput immersion AFM with 1nm 3D resolution

Sadeghian

2016

SPIE Proceedings

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Inspection of EUV mask substrates and blanks is demanding. We envision this is a good target application for massively parallel Atomic Force Microscopy (AFM). We envision to do a full surface characterization of EUV masks with AFM enabling 1 nm true 3D resolution over the entire surface. The limiting factor to do this is in the sensor itself: throughput is limited by the time that a cantilever needs to adjust its oscillation amplitude to the surface topography while scanning. We propose to use heavily damped cantilevers to maximize the measurement bandwidth. We show that using up to 20.000 cantilevers in parallel we can then reach a throughput of one 152 × 152 mm 2 substrate per 2 days with 1 nm resolution.

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Section: Introductionmentioning

confidence: 99%

EUV blank defect and particle inspection with high throughput immersion AFM with 1nm 3D resolution

Sadeghian

2016

SPIE Proceedings

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“…AFM is already used for several applications within the semiconductor industry, such as CD, and sidewall angle measurements [2,3], and defect inspection [4]. The major advantages of AFM over other imaging methods are the direct nature of the measurement, which allows to determine the position of each feature without extensive calibration of the metrology tool.…”

Section: Why Afm?mentioning

confidence: 99%

“…AFM imaging with over tilted AFM probes has been successfully demonstrated by several groups [2,4]. An additional advantages of this technique is that is allows to fully characterize the profile of the marker features.…”

mentioning

confidence: 99%

Large dynamic range Atomic Force Microscope for overlay improvements

et al. 2016

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Nowadays most overlay metrology tools assess the overlay performance based on marker features which are deposited next to the functional device features within each layer of the semiconductor device. However, correct overlay of the relatively coarse marker features does not directly guarantee correct overlay of the much smaller device features. This paper presents the development of a tool that allows to measure the relative distance between the marker and device features within each layer of the semiconductor device, which can be used to improve the overlay at device feature level. In order to be effective, the marker to device feature distance should be measured with sub-nanometer measurement uncertainty over several millimeters range. Furthermore, the tool should be capable of profiling the marker features to allows prediction of the location interpretation of the optical diffraction based alignment sensors, which are sensitive for potential asymmetry of the marker features. To enable this, a highly stable Atomic Force Microscope system is being developed. The probe is positioned relative to the wafer with a 6DOF controlled hexapod stage, which has a relatively large positioning range of 8x8mm. The position and orientation of this stage is measured relative to the wafer using 6 interferometers via a highly stable metrology frame. A tilted probe concept is utilized to allow profiling of the high aspect ratio marker and device features. Current activities are aimed at demonstrating the measurement capabilities of the developed AFM system.

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“…A small tip radius gives good resolution but high contact forces. The speed of AFM has been improved to a few mm/s [3], and it is envisioned that future systems will be capable of scanning at speeds as high as 100 mm/s. We will be considering an AFM system which is laterally scanning with this future speed of 100 mm/s on a surface with features i.e.…”

Section: Selection Of Afm Modementioning

confidence: 99%

“…Recent developments at TNO have led to a substantially increase of the speed of the measurement, hence, the process throughput [1][2][3][4][5]. A potential disadvantage of AFM can be that substrate or tip damage can occur because of tip-sample interactions.…”

Section: Introductionmentioning

confidence: 99%

High-speed AFM for 1x node metrology and inspection: Does it damage the features?

et al. 2015

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This paper aims at unraveling the mystery of damage in high speed AFMs for 1X node and below. With the device dimensions moving towards the 1X node and below, the semiconductor industry is rapidly approaching the point where existing metrology, inspection and review tools face huge challenges in terms of resolution, the ability to resolve 3D, and throughput.In this paper, we critically asses the important issue of damage in high speed AFM for metrology and inspection of semiconductor wafers. The issues of damage in four major scanning modes (contact mode, tapping mode, non-contact mode, and peak force tapping mode) are described to show which modes are suitable for which applications and which conditions are damaging. The effects of all important scanning parameters on resulting damage are taken into account for materials such as silicon, photoresists and low K materials.Finally, we recommend appropriate scanning parameters and conditions for several use cases (FinFET, patterned photoresist, HAR structures) that avoid exceeding a critical contact stress such that sample damage is minimized.In conclusion, we show using our theoretical analysis that selecting parameters that exceed the target contact stress, indeed leads to significant damage. This method provides AFM users for metrology with a better understanding of contact stresses and enables selection of AFM cantilevers and experimental parameters that prevent sample damage.

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Parallel, miniaturized scanning probe microscope for defect inspection and review

Cited by 9 publications

References 5 publications

EUV blank defect and particle inspection with high throughput immersion AFM with 1nm 3D resolution

EUV blank defect and particle inspection with high throughput immersion AFM with 1nm 3D resolution

Large dynamic range Atomic Force Microscope for overlay improvements

High-speed AFM for 1x node metrology and inspection: Does it damage the features?

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